# Measurement of a Preresonant Hyper-Raman Hyperpolarizability

## TL;DR

This paper introduces a method to measure a specific optical property using four-wave mixing spectroscopy, making it easier to quantify in various materials.

## Contribution

The study introduces an internal standard method for measuring hyper-Raman hyperpolarizabilities using CARS response.

## Key findings

- The hyper-Raman hyperpolarizability of acetonitrile ν(CN) was successfully measured.
- The internal standard method using CARS response from deuterobenzene is broadly applicable to infrared active vibrations.

## Abstract

Four wave mixing (FWM) spectroscopy is used to measure
a preresonant
hyper-Raman hyperpolarizability. The four wave mixing process known
as hyper-difference frequency generation (HDFG), which depends upon
the hyper-Raman hyperpolarizability, can be measured simultaneously
with other well-studied four-wave mixing processes, which serve as
an internal standard. We use coherent anti-Stokes Raman (CARS) response
from deuterobenzene to quantify the acetonitrile ν­(CN) hyper-Raman
hyperpolarizability. This internal standard method is applicable to
any infrared active vibration and greatly diminishes the barriers
to quantification of hyper-Raman hyperpolarizabilities.